摘要
山区隧道与地下工程的建设中多会穿越软弱夹层或破碎带等软弱地层。此类软弱地层几何形态变化大,力学性能差,隧道开挖后的收敛变形往往难以控制,这也成为山岭隧道施工以及结构设计的难点所在。着眼于软弱地层倾角对隧道围岩开挖变形的影响规律,利用模型试验,对无支护条件下软弱层围岩的拱顶、拱腰进行研究,监测了软弱层倾角分别为45°、60°、90°、120°、135°时隧道开挖造成的收敛变形;并结合数值模拟方法,进一步对比验证了模型试验的检测规律。结果表明:软弱层倾角对隧道围岩变形的影响十分显著。随着软弱层倾角的增加,隧道拱顶、拱腰以及仰拱的围岩位移先减小后增大。不同软弱层倾角下,通过归一化处理发现,拱顶和拱腰位置数值计算和模型试验的围岩位移变化结果呈现出高度的一致性。且根据监测面的塑性区云图,剪切破坏的区域贯通,分布于隧道一周,其面积随着软弱层倾角的增加,先减少后增大。
In the construction of mountain tunnels and underground projects,most of them will pass through weak layers such as weak interlayers or broken zones.The geometric shape of this kind of weak stratum changes greatly,the mechanical properties are poor,and the convergent deformation after tunnel excavation is often difficult to control.This has also become the difficulty of mountain tunnel construction and structural design.The law of the influence of the weak stratum dip on the excavation deformation of the surrounding rock of the tunnel is the object of study,the vault and arch waist of soft and weak layer surrounding rock under unsupported conditions were the studied parts through model experiments.The convergence deformation caused by tunnel excavation was monitored for soft layer inclination angles of 45°,60°,90°,120°and 135°respectively.Combined with numerical simulation methods,the detection rules of the model test were further verified by comparison.The results show that tunnel surrounding rock deformation is very significantly affected by the soft layer dip angle.The surrounding rock displacements of the tunnel vault,vault waist and invert arch decrease first and then increase with the increase of the inclination of the weak layer.The results of numerical calculations and model tests for the change of surrounding rock displacement at the arch top and arch waist positions show a high degree of consistency at different inclination angles by normalization.And the area of shear damage is continuous,distributed in a week of the tunnel,its area with the soft layer dip angle increases,first decreasing and then increasing through the monitoring surface of the plastic zone cloud map.
作者
康海波
李俊晖
赵刚应
熊维林
万志强
KANG Hai-bo;LI Jun-hui;ZHAO Gang-ying;XIONG Wei-lin;WAN Zhi-qiang(Highway Tunnel Branch of Sichuan Highway and Bridge Construction Group Co., Ltd., Chengdu 610200, China;School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China;School of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 610031, China)
出处
《科学技术与工程》
北大核心
2022年第19期8515-8522,共8页
Science Technology and Engineering
基金
四川省科技资助计划(2021YFH0037)。
关键词
山岭隧道
软弱层
数值模拟
相似模型试验
变形特征
mountain tunnel
weak layer
numerical simulation
similar model test
deformation characteristics
